Event Description

Networks of brain activity underlie our thoughts, emotions, and behaviors. A reliable set of brain networks is found in healthy people, and alterations are associated with individual differences in cognition, as well as with psychiatric disorders. All these findings assume a largely shared neural architecture from which such networks can be derived, and relative to which individual differences can be quantified. What are the functional networks that subserve preserved cognition in individuals with very abnormal brains? To address this question I will present data on intrinsic functional connectivity in rare patients who had surgical hemispherectomy in childhood due to severe epilepsy (in some cases involving the removal of the entire cortex, basal ganglia, thalamus, and amygdala in one hemisphere). All patients had relatively normal intelligence, and showed substantial compensation of sensory, motor, and cognitive functions that normally depend on the lesioned hemisphere. Remarkably, these patients showed largely normal brain networks, corresponding to those found in a single hemisphere of a healthy brain. The results support the idea of a shared set of brain networks for cognition, but also suggest subtle abnormalities in how these networks interact with one another to compensate.